In this study, we tested the following two hypotheses: (1) people who believe that some misinformation is true are more likely to spread it than those who do not believe in its truthfulness; (2) people with lower media and information literacy are more likely to spread misinformation than people with higher media and information literacy. The results of a logit model analysis of survey data using actual fact-checked COVID-19 vaccine and political misinformation supported the two hypotheses. The trend was also generally robust regardless of the method, whether the means of diffusion was social media or direct conversation.